Prior art systems for curing compost commonly utilize a concrete floor containing rectangular trenches in which is laid perforated pipe the ends of which are supplied air from a common plenum. The pipes are overlaid with a metal or plastic grating or gravel distribution system to permit front end loaders to traverse the floor to turn the compost periodically. A major problem of such systems is non-uniform air distribution resulting in unreliable curing of the compost. Another problem normally encountered in the use of such systems is clogging of the floor air vents necessitating shut down of the system until the vents have been cleared. A concomitant problem that results as the vents become clogged is that pressure required to maintain desired air flow increases. Consequently, blowers of increased capacity are needed to insure optimum curing conditions to offset the effects of variable back pressure caused by clogging of the air vents. The above problems result in unproductive down time with attendant increase in the cost of operation. The present invention ameliorates these problems. It is also to be noted that through use of the subject apparatus and method of operation the maintenance and effectiveness of the curing process is materially enhanced. The air channels are more easily accessed and cleaned and the overall costs of the curing system substantially reduced. Another aspect of the invention is the unique positioning of the system elements. Important factors in the siting of compost curing systems are the proximity of the system to populated areas and the required land area needed for operations. By positioning the biofilters in overlying relation to the curing floor as herein taught by applicant two major objectives are achieved. First, the area required for operations is reduced and secondly the filtering system is positioned to insure that effluents from the biofilter are emitted at higher elevations insuring that there is greater dispersion of effluent upon its release into the atmosphere. There is also provided a novel system for effecting dispersion of effluents during atmospheric inversions and for retaining and conserving water.